An automatic programmed controller for sequential laboratory operations

Abstract

A versatile device for carrying out routine laboratory operations in connection with experiments on thermal diffusion is described. It is instructed by a tape-recorder, has four separate information channels and has been applied here to set a series of different temperature gradients across a horizontal film of liquid, to record temperatures and temperature differences at various points in the system, and to record Schlieren traces of the refractive index gradients in the liquid films. It is also capable of stopping the tape-drive during a period when no new instructions are required, and then of re-starting it after a preset interval. This makes it possible to prolong the possible duration of the controlled experiments. Because of its flexibility it can be used to control almost any experiment which can be reduced to a set of sequential operations.